1. Technical Field
The invention relates to grinders, particularly to grinders which can grind fluid material into emulsion.
2. Related Art
To satisfy demands of users, the particle size of ground material becomes smaller and smaller. For example, in cosmetics, the particles must be ground to be the finest and emulsifiable so as to be easily absorbed by skin without harm. Thus the grinders must be very precision.
To achieve such grinding precision, conventional grinders add multiple knives, which are axially connected in series. By means of the centrifugal effect of rotation, the material to be ground are flung to the knives and then cut and ground. The axially arranged knives, however, cannot be reduced in volume. This will cause a problem of space utilization. Furthermore, because the material is flung by the centrifugal force, but the centrifugal force is hard to be controlled, the material is hard to be equably flung to the knives and to be equably ground. Finally, the grinding effect cannot satisfy the demand.
U.S. Pat. No. 6,250,573 provides a process and device for the dispersion of a fibrous paper material. '573 uses a gap between the teeth 7, 9 on the upper and lower grinding wheel to grind the material between the teeth. Although the teeth 7, 9 are radially arranged on the wheels to reduce its volume, the material flung by the turntable 5, especially liquid materials, tend to flow back due to the resistance of the teeth. The flow-back material will further resist the newly input materials. This causes a serious problem of material flow and grinding efficiency. This problem will become more serious if the material is syrupy.